It is a good idea to walk around the outside of the car and look at its bumpers, doors, roof and look for scratches and dents. We often are looking at the whole thing and not breaking it down into small groups. Look at the underneath. Is it rusty? Clean? Inspect the interior, not just it's gadgets. How are the seats? How does it smell? Does it look well cared for or just cleaned up? Open the hood. Look at the engine. Is there oil everywhere? Does it look overall clean for its age? You don't have to know everything about cars, looking at how a car has been cared for can say alot about what it's gone through in its previous life.